Etching-machine



H. OLSEN.

ETCHING MACHINE. APPLICATION FILED MAY 29,1916. RENEWED OACT. 6.1920.

1,383,01 0. Patented June 28, 1921.

UNITED STATES PATENT OFFICE.

,rtAaQLD onsnn, on NEW YORK, N. Y.,

BECKER, on NEW YOR;K, ,1\T. Y.; GEORGE BECKER, DECEASED.

' Ercnme-Mriciimn.

Application filed'May 29, 1916, Serial No. 100,574. Renewed October 6, 1920 Serial No. 415,218.

To all whom it mag concern:

Be it known that I, HAROLD OLSEN, asub ject of the King: of Norway, residing in New York city, county of New York, State of New York, have invented certain new and useful Improvements in Etching-Machines, of which the following is a full, clear, and exact specification.

This invention relates to etching apparatus and the object of the invention is to provide an improved machine which will project the etching fluid in a finely divided state against the surface of the plate to be etched.

It has been found that when the etching fluid is thrown perpendicularly against the surfaceof the plate,-the tendency to undercut is minimized. To so project the liquid machines have been devised which direct the acid onto the plate through numerous small nozzles, or by a rotary paddle wheel. The former or acid blast machines, are intricate, expensive and difficult to maintain in operation.' The rotary paddle wheel type of etching machine does not produce a finely divided spray andis limited'to low and practically "invariable velocity." The blades of the paddle wheel scoop up the liquid and throw it in masses against the plate and successive blades cannot operate efiectively unless the fluid surface has time between them to replace the liquid scooped out by each pre ceding blade. Due to the impact of the rotary sprayer blades with the liquid the operation of these paddle wheel 'machines is often disturbed by wasteful and troublesome vibrations.

It is the object of this invention to overcome these defects and provide a simple, smooth-running, inexpensive machine which will break up the etching liquid into a line spray and projectit'onto the plate velocity variable within wide limits. With this object in view a rotary member is pro videdgenerally circular in sectionfand in contactwith the etching liquid, a thin sheet of which 'adheresto the surface 0f the ro-' tary member at the area of contact. At a subsequent point in the rotation of the sprayer the thin sheet of liquid is thrown oilifrom the surface by centrifugal force, and the opposing forces due toadhesion and velocity act in such manner that the liquid is disintegrated into a fine spray and prowith a jected against the surface of the plate to be Specification of Letters Patent. Patented June 28, 1921i 1 etched. The speed of rotation of the runner and the velocity of the spray are readily va l riable within wide limits, higher speeds producing finer spray. The circular runner ofthis invention rotates in practically constant contact with the liquid, is free from the splashing and vibration usual with the paddle wheel type of sprayer and the resulting smoothness of operation 1 is attended with great gain in efficiency. 7

In the accompanylng ing the invention:

Figure 1 1s a perspective view of an etchlng machine embodying the lnvention, one

drawings illustratsideof the tank being broken away to show the interior.

Fig. 2 is a vertical section of the machine shown in Fig. 1.

Fig. 3 is a vertlcal sectional view. of another form of etching machine embodying.

the invention. 1 i

Fig. 4: is a partial elevation of a modiiiedf form of runner.

Figs. 5 and 6 are sectional. views illustrat-' ing modified runner surfaces.

In the embodiment illustrated in Figs. 1 and 2, 11s the etching liquid contained in closed tank, 2, having stand, 3, for support mg the plate, 4, to be etched at one end of the tank. At the other end of the: tank the.

rotary runner, 5, is on shaft dturningin bearings 7 1n the sldes of the/tank The runner 5 is of general cylindrical.

form and comprises a series of peripheral ridges, 10, with grooves, 11,.betweenthem having rounded convex bottoms. The axis of the runner is so placed that the grooved surface dips into the surface of the liquid. As the runner rotates the liquid adheres to its surface and is carried up with it. The irregular grooved characterJof the surface increases the area 111 contact and g ves a"? better hold on the liquid.

The film of liquid drawn up does tain immediately to the full velocity of'the not at runner surface. Where it leaves the body of the liquid there is considerable slip between the runner and the film butthe velocity of thefilm is gradually accelerated till it attains such a speed that the centrifugal forces acting are greater than the force of adhesion. The particles of the film'then fly off the periphery ofthe runner as a fine spray. Due to the irregular surface contour of the runner all parts of the film do not reach the'critical parting velocity at once. The liquid within the grooves is later to leave for it is more strongly held and its velocity is lower. It runs up the sides of the a grooves gradually and consequently the spraying action does not take place at a single line across the periphery of the runner but throughout a .considerable area. This spraying area is variable in extent and position by variations in the diameter and speed of. the runner and the size. and character of the grooves with relation to the charactor of the liquid being sprayed and the height of its surface. These factors are chosen to so locate this area that the spray is directed evenly over the surface of the plate 4. The velocity of the runner may be varied within wide limits, as by shifting the driving belt from one to the other of pulleys 13, While only slightlyaffecting the rate of.

etching, and the higher speeds produce finer and swifter sprays adapted for fine line work. r

To utilize the spray not directed against the plate, deflector guide 8 havinga depending lip 8 is mounted to overhang the'runner 5 and is made vertically adjustable. This guide is particularly important at high speeds and intercepts the upwardly directed spray and drips or deflects it back onto the runners,17, directing. their spray upwardly .Pivoted to stud 23 is the rod, 25,

between'the guides, 18. At the top of the tank 'is provided means for automatically" clamping and sustaining a plate face downward in the lineof the spray. The hinged cover, 20, carries the clamping block, 21,

fixed on its under surface. A sliding clamping'block, 22, is also provided, held on the cover by pivot stud, 23, sliding in slot 24:. sliding in the tubular rod, 26, pivoted to an offset of the tank, 19. A pin, 27, on rod 25 slides in a slot in rod 26 and limitstheinward movemerit-of rod v25. A compression spring, .28,

presses against the pin 27 to draw the rod 7 liquid and 25 into the rod 26. I

The parts are so proportioned and the pivots-so arranged that when the cover 20 is open and inclined backward, as shown in dotted lines, pin 27 is at the bottom of the slot in rod'26 and stud 23 is at the top ofslot24. In this position a plate, 30, to be etched is placed between the proper steps grooves, 38.

comparison to its diameter, for the liquid leavesthe deep grooves, 38, only, gradually.

' of the clamping blocks 21, 22. 'As thecover,

.ing aws.

In Fig. 1 is shown a modified form ofrunner in which the ridges, 35, and grooves, 36, are in theform of a helix. By this ar-' rangement continuous horizontal displace ment of the spraying surfaces is attained with a more uniform distribution of the spray. e

In Fig. 5 is shown in section a form of runner contour in which the disks or ridges, 37, are separated by. relatively narrow Such a form of runner is." adapted to give a large area of spray in Fig. 6 shows a section'of a runner contour.

in which the ridges 39 and 40 form undercut grooves between them. To break-the continuity of ridges 39grooves 41 are formed in them. I. It is evident that the strength and the relative surface heightof the etchingsfluid may be varied to control the etching eflect. The runner peripheryinstead of being perfectly cylindrical may be tapered at theends: or otherwise altered in contour to properly locate the main body of the spray. It, is also apparent thatthe etching liquid may be poured or sprayed onto the runner surface and that the form of sprayer herein disclosed may be used to project other liquids. It is to be understood thatthe invention is not confined to the particular embodiments described but covers such modifications thereof as fall within the scope of. the ap-[ pended claims.

Having thus described my invention what I claim to be new and'desire to secure by Letters Patent is r 1. In an etching machine the combination i with a tank for the etching liquidhaving a support for. the plate'to be'etched of a circular member having continuous grooves extending around-its periphery adapted to rotate in constant contact with-the etching project said liquid against said plate. V V w 2. In an etching machine a rotary member having spaced grooves onj'its periphery extending substantiallyin the direction ofro tation andadapted to rotate in contact with the etching fluid to disintegrate said fluid, into a spray. V v

3. In an etching machine a rotary c linder having a helical groove on its perip er adapted to rotate in constant contact wit the etching liquid and acting to disintegrate said fluid into a spray.

4. In an etching machine, the combination with a tank for the liquid and a support for the plate, of a rotary projector comprising a circular member substantially cylindrical in form and having spaced grooves extending around its periphery in the general direction of rotation of the member, and means for rotating said member at different speeds.

5. A centrifugal liquid spraying means, comprising a circular member adapted to rotate in contact with the liquid and having peripheral ridges separated by shallow grooves with bottoms normally contacting with the surface of the etching liquid.

6. In an etching machine a tank containing spraying means for projecting the liquid upwardly, a pivoted tank cover carrying fixed and sliding clamping blocks, and an extensible link connecting between said sliding block and said tank acting to automatically move said block on movement of said cover.

7. A liquid spraying means comprising a rotary member having a series of closely spaced ridges extending around its periphery and adapted to rotate in contact with the etching liquid and project said fluid from said periphery by centrifugal force, and means for rotating said member.

8. In an etching machine the combination with a container for the etching fluid and a holder for the plate to be etched, of a rotary sprayer having generally circular sections of variable diameter at successive points along the axis of rotation, the periphcries of said sections being in contact with the etching fluid and acting to project said fluid against said plate b centrifugal force.

In testimony whereof have hereunto set my hand this 29 day of April, 1916.

HAROLD OLSEN. 

